Photos app main view mode rendering photos too bright / thumbnails correct

Hi all

Noticing strange behaviour in Mac Photos main viewer/editing mode. Many recent photos are rendering with blown-out highlights. These are just regular iPhone photos. When I open via Raw Power or export the photos they show-up normal. Also, when I move the Photos window to my external display they also show-up normal. When I flick through different photos and videos I can sometimes see the change happening in front of my eyes - at first normal then changes to blown. Unaffected on my iPhone Photos app.

See attached screenshot.

Am running p u b l i c b e t a so perhaps this is an issue there to be reported if above is unexpected behaviour to people here.

Ross